A power device detachably installed with a battery is known in the art. When the battery is removed from or installed in the power device during operation (hot swapping), an inrush current flows from the power device to the battery or from the battery to the power device in some times. This inrush current may generate a failure of the power device or the battery, or an electrical shock accident.
A battery management unit (BMU) is known in the art as a unit for preventing a failure of the battery caused by a large current such as the inrush current.
However, as the number of detachable batteries increases, a throughput of the battery management unit increases, and a configuration of the power device becomes complicated.